1. Field of the Invention
The invention relates generally to equipment for assisting in improving balance, and more particularly, to a balancing board with an adjustable pivot to vary the difficulty of balance for the user.
2. Discussion of the Related Art
Balancing boards of various designs have been used for years to strengthen and train a person's muscle groups to maintain their body in balance. One popular design for a balancing board consists of a platform on which a person will stand and a stationary fulcrum attached to a center point of a bottom surface of the platform. In use, the fulcrum contacts a surface (e.g., a floor or the ground) on which the balancing board is supported, and may take on a variety of shapes, such as a partial hemisphere, a full or partial cylinder axially aligned in the horizontal plane, or other shapes having a curved or angled surface extending below the platform bottom surface. With a balancing board having a fixed fulcrum and a hemispherically-shaped surface, the board is pivotable to some degree about any axis in the plane of the surface upon which it is resting; if the fixed fulcrum instead has a cylindrically-shaped surface, the board is pivotable about the longitudinal axis of the fulcrum and may only be pivotable about a transverse axis in the plane of the surface if the user positions their center of gravity outwardly towards a perimeter of the platform at or beyond a point vertically above the end of the fulcrum. Another balancing board design implements a moveable fulcrum in place of a stationary fulcrum. One example of a movable fulcrum includes a roller or wheel rotatable along the bottom surface of the platform. Because the movable fulcrum may be disposed at a location away from the center point of the bottom surface of the platform, thereby providing no vertical support beneath the center of gravity of the platform, more challenge is introduced to the user to maintain their balance while keeping the platform in equilibrium above the surface upon which the fulcrum is resting.
Further advancements have led to balancing boards designs that have an adjustable range of difficulty. As an example, U.S. Pat. No. 5,810,703, issued to Stack, provides a balancing board with a fulcrum having a hemispherically-shaped contact face and a spacer placed between the fulcrum and the platform. The spacer allows the contact face to be positioned at various heights relative to the platform such that varying degrees of allowable rotation of the platform about any axis in the horizontal plane are realized. Novices would select a smaller degree of rotation such that if they were to get out of balance while using the balancing board, the perimeter of the platform would quickly contact the surface upon which the fulcrum is resting and allow them to easily regain their balance. Alternatively, a larger degree of rotation would be selected by more experienced users who wish to regain their balance more by using their own muscles and less with the aid of the platform.
While the balancing board of Stack provides general balancing difficulty adjustment, such an adjustment can only be made for all directions of rotation about any axis in the plane of the surface upon which the fulcrum is resting, and with the same degree of rotation. This is problematic for a user who wishes to increase difficulty in one direction of rotation, such as fore and aft rotation, while selecting a different level of difficulty in another direction of rotation, such as lateral rotation. Other balancing boards employing a moveable fulcrum have some degree of balancing difficulty adjustment, but these devices involve rather complicated designs with a number of moving parts to maintain, and generally do not provide for separately adjusting the difficulty of balance depending on the particular axis in the plane of the surface about which the board is rotating.